Effect of deformation on aging in Al-Mg₂Si alloys

The effects of deformation on the aging in five kinds of Al-Mg₂Si alloys have been investigated by Vickers microhardness test and electron microscopy. In Al-0.4%Mg₂Si alloy, the maximum hardness during aging was small. Both intermediate and equilibrium phases were detected in the specimen peak-aged at 473 K without predeformation, though no equilibrium phase was observed in cold-rolled and peak-aged specimen. In Al-1.0%Mg₂Si and Al-1.6.%Mg₂Si alloys, there were several combinations of cold-rolling and aging condition under which the maximum hardness of the non-deformed specimens was nearly equal to that of the deformed specimens. In Al-0.4%Mg₂Si and Al-0.6%Mg₂Si alloys, the age hardenability, which is given by the difference between the maximum hardness and the initial hardness is larger in cold-rolled specimen than in non-rolled specimen. However, the age hardenability of both Al-1.0%Mg₂Si and Al-1.6.%Mg₂Si alloys is larger in non-rolled specimens than in rolled specimens.